Method of delivering a mixture of gas and air.



G. KEHH.

METHOD OF DELIVERfNG A MIXTURE 0F ms mm AIR.

APPLCATIGN LED SEP I '9- 1935. 1,301,272. Patented Apr. 22, 1919.

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METHOD OF nwvenme A MIXTURE 0r GAS AND AIR. APPLICAHDN FILED SEPT 19. I916.

Patented Apr. 22, 1919.

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nu mum: urn! m. puomulmx, v -mumom n c UNITED STATES GEORGE KEITH, OF LONDON, ENGLAND, ASSIGNOR 0F ONE-HALF TO JAMES KEITH, OF

LONDON, ENGLAND.

METHOD OF DELIVERING A MIXTURE 0F GAS AND AIR.

To all whom it may concern Be it known that I, GEORGE KEITH, a subject of the King of the United Kingdom of Great Britain and Ireland, and residing at London, England, have invented a certain new and useful Improvement in Methods of Deliveringa Mixture of Gas and Air or Oxygen for Combustion, of which the following is a: specification.

This invention relates to an improved method of delivering a mixture of gas and air or oxygen) for combustion, for example, in a gas-fired furnace, oven or other installation, and it has for its primary object to render practicable the maintenance of the correct proportions of gas and air (or oxygen) irrespective of variations in the quantit of the mixture being dealt With.

The improved method consists broadly in injecting one of the constituents of the mixtureand ihducingthe flow of the other constituent, while governing the pressure of the induced constituent to maintain the pressure proportionate to the resistance offered to the flow of the mixture, whereby variation in the resistance of the nozzle, of the furnace or the like being fired, or of the flue, may be automatically compensated for-it being under stood that variation in the quality of the mixture must otherwise result from variation in the resistance to be overcome.

In this connection it may be pointed out that variation of the resistance may be due to variable heating up of the mixture before it issues from the nozzle, fluctuationof the tempratfii-e in the furnace or the like and consequent variation in the contraction of the products of combustion, introduction or withdrawal of materials being heated, opening or closing of doors or of dampers, variatlons of pressure in the flue, or to other causes, and that b the present invention the effect on the qua ity of the mixture of all such possible causes of variation may be automatically compensated for.

The preferred form of overning device employed comprises a diap ragm casing in which is fitted a thin membrane openatlvely connected with a valve servin to regulate the admission to the casing o the induced medium, the compartment of the casing at the back of the diaphragm being in communication With a point In the path of flow of mixturepreferably on the delivery side of the injectorso that it is influenced by Specification of Letters Patent.

Patented Apr. 22, 1919.

Application filed September 19, 1916. serial No. 121,030.

variations in the static pressure obtaining in that part of the injector.

In certain cases, Where the induced niedium is gas, it may be sufficient for the purpose in view so to govern the as pressure that the gas is previously brought to a pres sure equal to that prevailing at the final outlet for the products of combustion, e. 9., to atmospheric pressure, if the final dischar e be directly into the atmosphere, or to t e pressure prevailing in the chimney.

In case the gas pressure is to be maintained at atmospheric pressure, the back of the diaphragm may be left open; if the gas is to be brought to a pressure equal to that prevailing in the chimney, the connection from the back of the diaphragm may be led to the chimney.

The invention is illustrated by wa of example in the accompanying drawings in which Figure 1 is a vertical section showing the diaphragm casing and injector with a connection from the back of the diaphragm to a point on the delivery side of the injector. Figs. 2, 3 and 4 represent diagrammatically three forms of connection. Fig. 5 is a vertical section through the diaphragm casing.

In the construction shown, the governor is designed to govern the pressure of gas gas being the induced medium, and the in jected medium being air or oxygen. It will be understood, however, that with suitable modification the governing device ma be adapted to govern the ressure of the a r or oxygen wher the induced medium is air or oxygen and the injected medium is R feriihg to the drawings, 1 denotes the diaphragm casin in which is fitted a thin membrane 2 whic is referably disposed in a vertical plane to eliminate the effect of weight and is operatively connected with a valve 3, preferably constituted as a balanced butterfly valve of substantially elliptical form, adapted to be seated on the machined internal surface of a cylindrical valve casing 4 in communication with the gas inlet 5it being understood, however, that any suitable form of valve, balanced or otherwise, may provided.

, The valve 3 is so mounted as to be immovable laterally though not liable to be jammed with grit or the like, being carried by a hinge in passin through lugs On a bracket mem er 6 fittecfwithin the casing 4.

The membrane 2 is operatively connected with the valve 3 by a closely wound helical 5 ring 7 one end of which is connccted to the membrane 2 and the other end of which is connected to the valve-operating lever 8, 5 the spring being of suflieient strength to msure that the valve 3 shall be properly closed when the spring 7 is stressed but bein rapable of further extension in case of suc 1 accumulation of pressure of the gas on the 10 membrane when the outlet of the governor is closed as to move the membrane against the face of the diaphragm casing-the arrangement being such as to obviate straining of the valve.

he connection between the bark of the diaphragm and the injector is represented by a tube 9 which is led to the expansion tube 10 of the Venturi tube and which may terminate flush with the internal wall of the Venturi tube with its mouth facing across stream, as in Figs. 1 and 4, or may project into the interior thereof with its mouth facing u stream, as in Fig. 2, 0 down stream, as in Fig. 3, or in any intermediate position, according as it is intended to establish pressure above or below that of the mixture in the expansion tube having regard to the conditions of construction and operation.

Whichever of the arrangements described be adopted, increase or decrease of the resistance oflered to the flow is instantaneously responded to by the governor, the consequential alteration of the pressure of the gas sup ply to the injector resulting in maintenance of the uniformit of quality of the mixture.

It is to be un erstood that the connection to the back of the governor diaphragm need not be taken from the expansion tube but may be conveniently taken from any point between the inlet of the injector and the burner nozzle, or even from the furnace itself,

although in the last mentioned case there will be no provision for compensation in re spert of expansion before passage of the mixture through the nozzle.

To effect the initial adjustment of the proportions of gas and air or to effect any desired variation in the adjustment, a cock 12 or its equivalent is fitted in the connection 11 for delivering gas from the diaphragm casing 1 to the injector.

The cock 13 serves to regulate the supply of air to the injector.

While the apparatus illustrated is articularly applicable for delivering a se f-burning mixture of gas and air to gas-fired furnaces, it is to be understood that the invention is not confined to such application, but includes the delivery of gas and air (or oxygen) in given proportions to ovens, burners or other installationswhether the mixture to be consumed be self-burning or otherwise.

If air (or oxygen) be the induced medium, the governing device will, of course, be interposed in the air (or oxygen) inlet connection and will serve to govern the pressure of the air (or oxygen) admitted,-while the gas connection will be taken to the nipple of the injector.

What I claim is The herein described method of delivering a mixture of gas and a comburent me dium for combustion, consisting in injecting the entire volume of one of the constituents of the mixture and thereby inducing the flow of the induced constituent and governing the pressure at which the induced constituent is supplied in direct roportion to the fluid ressure of the said mixture.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GEORGE KEITH.

Witnesses HENRY MASON, ISABEL RoLLo.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patent Washington; D. O. 

